The True Theory of Evolution is about Cooperation and genes
what differentiated cats from lions?
Cats and Lions came from the same genetical root. We don't need to deep dive into the composition of their genes to understand that they are from the same family of animals, genres, felines.
We use to think that lions were way bigger than they actually are and it seems that we discovered some vestiges of ancient lions in Kenya that look like This
What I strongly believe is that lions were small like cats but they have grown and become bigger not only by natural circumstances like the number of resources they had or their habitat. The truth is that at some point in time in history some groups of felines started cooperating rather than living alone or in couples. They socialized and started doing things together like hunting. As they started hunting in groups, tribes, or families, they just were able to reach bigger prey and have more food to feed themselves. These felines that adopted social living standards started to be bigger generations by generations while the others that were not cooperating stagnated in terms of weight. The fact that they hunted different and bigger preys transformed profoundly their morphology.
This is just a short article to claims that if cougars, leopards, jaguars, lions, and their peers are bigger than cats it is mainly because their grandparents were the ones who accepted living in tribes while the grandparents of these actual cats we see had not. This is the main change that made lions-like feline strong like they are today.
This simple behavioral change is at the root of all these differences they have in terms of weight and power.
PS: their habitat has something to do with the evolution of the patterns of their skin.